Laminated spring



, July 28, 1925.

G. A. WOODH EAD LAMINATED SPRING Filed/Nov. 14. 1924 flffarney.

Per.

Patented July 28, 1925.

GEORGE ALFRED WOODHEAD, 0F LEEDS, ENGLAND.

LAMINATED SPRING;

Application filed November 14, 1924. Serial No. 749,896.

To all whom it may concern:

Be it known that I, GEORGE ALFRED VVoon- HEAD, a subject of the King of Great Britain, residing at The Grange, Old Park Road, Roundhay, Leeds, England, have invented certain new and useful Improvements in or Relating to Laminated Springs, of which the following is a specification.

This invention has reference to laminated springs for use more particularly on motor driven vehicles although the invention is not confined exclusively to this type of laminated spring.

here, as in automobiles, particularly,

laminated springs are constantly subject to shocks of a more or less severe order some means is desirable for checking the tendency to rebound or bounce consequent on the sudden removal of the load. z

Apart from the bad effect on the suspension system generally this tendency to rebound or bounce is largely responsible for spring failures, and also for skidding by reason of the vehicle not holding to the road as it should do. a a, a

This inherent defectvof the present type of laminated spring has in fact given rise to the common practice on road vehicles of fitting special shock absorbing devices having for their exclusive object to counteract the injurious effect of main springs. The objectof thevpresent invention is to construct the main springs themselves in such a manner as to eliminate, or at least very much reduce, the rebound tendency and so as to render the fitting of auxiliary shock absorbing devices quite unnecessary.

Rebound plates superimposed upon the main leaf and opposed to the series of plates constituting the spring proper have been employed to check the rebound tendency but with indifferent success in many instances because unless fitted with considerable nip their free ends tend to separate from the main spring and from each other at the identical moment in the movement of the spring when their close co-operation with the latter is essential to check rebound.

Where rebound plates are fitted, with nip, as when they are made flat or of opposite camber to that of the main spring a permanent initial stress is necessarily set up both in the rebound plate or plates and to a more or less extent, in the main spring itself. r v

the rebound of the According to this invention the rebound plate or plates is or are so arranged with respect to the main spring that they form at all times an integral part of the weightcarryingsystem of the latter, that is to say, theyare made of the same camber as that of the main leaf and positively secured to the main spring at or near their free ends. An important advantage accruing from this formation of the rebound plate or plates'is that when the spring is assembled no initial stresses are set up either in the rebound plates or, taken as a Whole, in the main spring itself. v

A, further noteworthy feature of the invention apart from the'reduction or elimination of bounce or rebound is that for a given load the improved spring need not contain any more steel than a spring of ordinary design so that the present inven tion is further characterized in that there need be no increase of Weight.

As already stated the rebound plates are positively secured to the main spring and consequently bear their share of the load and one of the most efficient ways of accomplishing this end, which also checks lateral movement of all the plates both rebound and ordinary, is to employ an arrangementin which each orcertain of the superimposed rebound plates is or are formed at their ends with solid lugs to receive clips which embrace the leaves opposedthereto on the normal side of the main leaf, or vice versa, that is to say, the lugs may be formed solid with some of -the leaves of the ordinary spring, the clips embracing the rebound plates. It is not however proposed to confine the present invention to the use of this particular form of clip since any device that will maintain the various plates of the improved I spring at all times in close contact with each other and prevent lateral displacement of the same will be found to answer the purpose of the invention.

In order that the invention may be clearly understood and readily carried into practical effect reference is made in further describing the same to the accompanying.

drawing, wherein,

Figure 1 shews by Way of contrast or comparison a laminated spring of the ordinary conventional type.

Figure 2 represents one'example of a spring constructed in accordance with this invention; i

Figu ze 3 shewspthe plates or leaves of the spring shown in Figure' 2 separated.

Figure at represents a spring in which theapplication of the present is c'ar rled to its logically extreme polnt.

Throughout the drawing like parts are designated by similar reference characters.

Referring to the d'rawi11g,-a represents the usual top plate, back plate or main lea'l 6*thefoi'di1i2'iry plates and 0 theflrebonnd plates, whilst 'd"indicate the clips.

-The're may be one onlybr any tesired number" of rebound plates 0 superimposed upon the maindeaf orlback plate a but,

whereas theyh'ave beenhi'therto fitted with nip, th'ey"are"'formed according to the present lnvention so that 111 their-normal unstressed st'atej'tliey will lie in close and uniforjnr contact with the main leaf and with each other" when thesprmg is assembled; In acambered spring therefore each' rebound plate, as 'SEGITIRQFIQ'UIQ 3,1

is of the same camber as that ofthe main leaf and consequentlyno initial stress is set upeither in the rebound plates or, tauen as awliole,1n the ma1n'spr1ng itself when V the spring 1s made up) The spring shewn i'n FigureQ is by way of example only and serves to illustrate two points, firstlythatthre may be many 'rc bound plates asthere areplates on the normal side-Got the main leaf'and secondly,

- that thegtotal number of plates and there tore the weightof"jthe improved spring neednot exce'eclthatof an ordlnary spr ng,

Figure lld'for the same "service. H

VVhi lst as already statedthere may he any desired number of rebound plates the-re need"notfnecessarily be any plates: whatever on the normal side of "the main leaf, as isjrepresented in'Figure tandit is to be observed that in a spring built up in this way with equally cambered plates, there is an 7 entire [absence of'initial stress, the

whole ot' the material comprising the spring being technically at rest when the latter is not underload; 3

The'chps (Z as" shewn are of U-shaped with reduced and screw threaded free ends which are passed throng-hand secured by, nuts to perforated lugs e formed: integral 1 wwith and j ro'ectino laterall from the y l n 3 ends of eaclro'fthe rebound plates 0. Ohviously this arrangement can be reversed and the free ends of the clips passed through andisecured biynuts to lugs on the ends or" plates together without interfering with their relative freedom of action when under a varying l0ad.;- i

3. A laminated spring comprising a main plate, a rebound plate-inadeto lie without stress in uniformcontacttherewith, a supplem jentary plateion the opposite side of the main plate and means for securing: the three plates together without; interfering with their relative freedom of action when under a varying load.

4. A laminatedspringcomprising a main plate, a plurality of rebounclwplates ot graduated lengths made to lie without stress: inifuniform contact therewith and with each other, a supplementary plate on the opposite side of the nain plate and {means for securing the plates together without inter feri'ng with their relative freedom of act-ion when under a V2tl'yl1'lg-102Ld. I

5. A laminated A spring comprising I a main plate, a rebound plate .inade to lie without stress" in unifornr Contact therewith,- 1 a plu- T ralityof supplementary "plates of graduated lengths at the opposite side ot]the main plate and means for securing theiplates to-i: gether without interfering with their rela- 1 tive freedom of action whennnder avarymg load, a a

6 A laminated spring "comprising a main plate,-ai plurality} of rebound plates of graduated lengths superimposed thereon and made to lie without stress-in uni-form contact with each other and with the main plate, and a plurality of supplementary plates of graduated lengths onthe opp0- site side ot themain plate and means for securing the platesl together withoutinterfering with their relative g freedom of action when under a varying load.

7; A laminated spring comprising a main plate, a rebound plate having laterally pro-- jecting perforated lugs at each end and; madeto liewithout stress in uniform contact with theflmain plate and a pairwof clips each adapted to embracesaid plates and to be secured to said lugs.

8. A laminatedspring comprising a main plate, a plurality vof reboundiplatesi of graduated lengths made to liewithout stress in "uniform contact with a each other 1 l and with the main plate andhavingpertorated laterally projecting ilugs fat their ends" and a plurality of clips eachfernbraeinga more or less number of the. platesand adapted for U several attachment to said lugs-.5 I

9. A laminated spring comprising men plate, a rebound plate having laterally projecting perforated lugs at each end and made to lie without stress in uniform contact with the main plate, a supplementary 3 plate on the opposite side of the main plate and a pair of clips embracing the-three plates and adapted for attachment to said lugs.

10. A laminated spring comprising a main plate, a plurality of rebound plates of graduated lengths made to lie Without stress in uniform contact with each other and with the main plate and having perforated laterally projecting lugs at their ends, a supplementary plate on the opposite side of the main plate and a plurality of clips each embracing a more or less number of the plates and adapted for several attachment to said lugs.

11. A laminated spring comprising a I main plate, a plurality of rebound plates of graduated lengths made to lie Without stress in uniform contact with each other and With the main plate and having perforated lugs projecting laterally from their ends, a plurality of supplementary plates of graduated lengths on the opposite side of the main plate and a plurality of clips adapted for several attachment to said lugs and embracing a more or less number of all the plates.

GEORGE ALFRED WOODHEAD. 

